You can clearly make out his mouth and grin. His eyes are definitely there and you can't deny that's a red gloved fist. It's definitely not Sonic's jumping sprite, it's a monster and out of all the conceptual monsters we have...he resembles the purple ghost guy the most.

Wow, this has to be one of the best discoveries regarding Sonic 1 Beta we've gotten in a long time; the enemies were actually sprited and programmed (at least one, and so it seems he was programmed) at one point. Great job everyone.

If it really is true with that blurred image being one of the monsters, then it makes me wonder how the other enemies would have behaved. Even the guy in the background could have been the potential boss and I can't even imagine just how different Sonic would have been had the game gone down that path. Man this beats any find that has been discovered in the past I can honestly say my mind will be blown if the clearer pictures confirm it.

...if he attacked by jumping, wouldn't that mean he shared both palette and functionality with Splats?

We don't know for certain which palette Splats used.

From the Wiki:

Quote

Splats is depicted in secondary sources (merchandise etc.) as being grey with blue highlights. The sprite however, is blue with orange highlights when using Sonic's palette line. It could also use the second palette line, which varies from level to level either purple or green.

I stand corrected, there definitely is a thing there. So odd that nobody knew of it after all these years...

Makes me think we're about due for a hack which features those weird monsters as enemies. Maybe the next time someone interviews the Sonic 1 team they should have a question about how many of the monsters wound up in the game, and what they did, if anything.

I also realized the weird buildings from the concept art are also in that demo. So that build, lost to history as it is, probably was a proper implementation of many of the early concepts. Huh.